Bulk acoustic wave resonator sensor

Abstract

A bulk acoustic wave resonator (BAWR) sensor is provided. The BAWR sensor includes a signal BAWR that measures a resonance frequency that is modified due to a reaction with a target material, a reference BAWR that measures a reference resonance frequency without reaction with an external environment, and a sensing unit that senses the target material, based on the modified resonance frequency and the reference resonance frequency.

What is claimed is: 
     
       1. A bulk acoustic wave resonator (BAWR) sensor, comprising:
 a signal BAWR comprising
 a first substrate comprising a first via-hole formed in a lower side of the first substrate and a second via-hole formed in the lower side of the first substrate; 
 a first bulk acoustic wave resonance unit comprising a first air cavity formed on a top of the first substrate, a first lower portion electrode formed on top of the first air cavity, a first piezoelectric layer formed on top of the first lower portion electrode, a first upper portion electrode formed one top of the first piezoelectric layer, and a first coated layer, and 
 a first resonance frequency measuring unit configured to measure a resonance frequency modified by the sample using the first lower portion electrode and the first upper portion electrode, wherein the first resonance frequency measuring unit is connected to the first lower portion electrode through a first electrode pad within the first via-hole, and is connected to the first upper portion electrode through a second electrode pad within the second via-hole; 
 
 a reference BAWR configured to measure a reference resonance frequency without reaction with an external environment; and 
 a sensing unit configured to sense the target material, based on the first modified resonance frequency and the reference resonance frequency. 
 
     
     
       2. The BAWR sensor of  claim 1 , wherein:
 the signal BAWR comprises: 
 a second substrate comprising a second air cavity formed on a predetermined area of a lower side of the second substrate, and connected to the first substrate; 
 a first in-channel through which a sample including the target material flows in; and 
 a first out-channel through which the sample including the target material flows out, and 
 the reference BAWR comprises: 
 a third substrate; 
 a second bulk acoustic wave resonance unit comprising a third air cavity formed on a top of the third substrate, a second lower portion electrode formed on a top of the third air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, and a second upper portion electrode formed on top of the second piezoelectric layer; 
 a fourth substrate comprising a fourth air cavity formed on a predetermined area of a lower side of the fourth substrate, and connected to the third substrate; and 
 a second resonance frequency measuring unit configured to measure the reference resonance frequency using the second lower portion electrode and the second upper portion electrode. 
 
     
     
       3. The BAWR sensor of  claim 2 , wherein the first coated layer is coated with a base material configured to react with the target material to sense the target material from the sample. 
     
     
       4. The BAWR sensor of  claim 2 , wherein the first coated layer is located on the top of the first upper portion electrode or under the first lower portion electrode. 
     
     
       5. The BAWR sensor of  claim 2 , wherein the reference acoustic wave resonator further comprises a second in-channel through which the sample including the target material flows in and a second out-channel through which the sample including the target material flows out. 
     
     
       6. The BAWR sensor of  claim 2 , wherein:
 the third substrate comprises a third via-hole formed in a lower side of the third substrate and a fourth via hole formed in the lower side of the third substrate; and 
 the second resonance frequency measuring unit is connected to the second lower portion electrode through a third electrode pad in the third via-hole, and is connected to the second upper portion electrode through a fourth electrode pad in the fourth via-hole. 
 
     
     
       7. The BAWR sensor of  claim 2 , wherein the first in-channel and the first out-channel are further configured to allow the sample to flow in and out from an external side to the second air cavity, through a hole formed on the second substrate. 
     
     
       8. The BAWR sensor of  claim 2 , wherein the second substrate includes a transparent material so that occurrence of a reaction in the coated layer and an intensity of the reaction are monitored. 
     
     
       9. The BAWR sensor of  claim 2 , wherein the first substrate and the second substrate are connected to each other based on an anodic bonding scheme or a eutectic bonding scheme. 
     
     
       10. The BAWR sensor of  claim 2 , wherein the first lower portion electrode, the first piezoelectric layer, the first upper portion electrode, and the first coated layer are sequentially laminated on the top of the first air cavity; and
 the second lower portion electrode, the second piezoelectric layer, and the second upper portion electrode are sequentially laminated on the top of the third air cavity. 
 
     
     
       11. The BAWR sensor of  claim 1 , wherein:
 the reference BAWR comprises: 
 a second bulk acoustic wave resonance unit comprising a second air cavity formed on the top of the first substrate, a second lower portion electrode formed on top of the second air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, and a second upper portion electrode formed on top of the second piezoelectric layer; and 
 a second resonance frequency measuring unit configured to measure the reference resonance frequency using the second lower portion electrode and the second upper portion electrode, and 
 the signal BAWR and the reference BAWR comprise: 
 a second substrate comprising a third air cavity formed on a predetermined area of a lower side of the second substrate, and connected with the first substrate: 
 an in-channel through which a sample including the target material flows in; and 
 an out-channel through which the sample including the target material flows out. 
 
     
     
       12. The BAWR sensor of  claim 11 , wherein:
 the first substrate comprises a third via-hole formed on a predetermined area of a lower side of the first substrate; 
 the second resonance frequency measuring unit is connected to the second lower portion electrode through a third electrode pad in the third via-hole, and is connected to the second upper portion electrode through the second electrode in the second via-hole. 
 
     
     
       13. The BAWR sensor of  claim 11 , wherein the in-channel and the out-channel are further configured to allow the sample to flow in and out from an external side to the third air cavity through a hole formed on the second substrate. 
     
     
       14. The BAWR sensor of  claim 1 , wherein the reference BAWR comprises:
 a second bulk acoustic wave resonance unit comprising a second air cavity formed on the top of the first substrate, a second lower portion electrode formed on top of the second air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, and a second upper portion electrode formed on top of the second piezoelectric layer; 
 a second substrate comprising a third air cavity formed on a predetermined area of a lower side of the second substrate, and connected to the first substrate so that the second bulk acoustic wave resonance unit is isolated from the external environment; and 
 a second resonance frequency measuring unit configured to measure the reference resonance frequency, through the second lower portion electrode and the second upper portion electrode. 
 
     
     
       15. The BAWR sensor of  claim 1 , wherein the sensing unit comprises:
 a database unit configured to store predetermined information corresponding to the modified resonance frequency; and 
 a matching unit configured to match the modified resonance frequency and the stored predetermined information. 
 
     
     
       16. The BAWR sensor of  claim 1 , wherein:
 the first air cavity is formed on top of the first substrate so as to detect a first characteristic of the target material; 
 the signal BAWR comprises: 
 a second bulk acoustic wave resonance unit comprising a second air cavity formed on the top of the first substrate so as to detect a second characteristic of the target material, a second lower portion electrode formed on top of the second air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, a second upper portion electrode formed on top of the second piezoelectric layer, and a second coated layer; and 
 a second resonance frequency measuring unit configured to measure a second resonance frequency modified by the sample, through the second lower portion electrode and the second upper portion electrode; and 
 the sensing unit detects the first characteristic of the target material based on the first modified resonance frequency, and detects the second characteristic of the target material based on the second modified resonance frequency. 
 
     
     
       17. The BAWR sensor of  claim 1 , wherein the sensing unit is further configured to sense the target material based on a difference between the first modified resonance frequency and the reference resonance frequency exceeding a predetermined value. 
     
     
       18. An analysis device comprising:
 a bulk acoustic wave resonator (BAWR) sensor unit comprising:
 a signal BAWR configured to measure a resonance frequency that is modified due to a reaction with a target material, the signal BAWR comprising:
 a first substrate comprising a first via-hole formed in a lower side of the first substrate and a second via-hole formed in the lower side of the first substrate; 
 a first bulk acoustic wave resonance unit comprising a first air cavity formed on a top of the first substrate, a first lower portion electrode formed on top of the first air cavity, a first piezoelectric layer formed on top of the first lower portion electrode, a first upper portion electrode formed one top of the first piezoelectric layer, and a coated layer; and 
 a first resonance frequency measuring unit configured to measure a resonance frequency modified by the sample using the first lower portion electrode and the first upper portion electrode, wherein the first resonance frequency measuring unit is connected to the first lower portion electrode through a first electrode pad within the first via-hole, and is connected to the first upper portion electrode through a second electrode pad within the second via-hole; 
 
 
 a reference BAWR configured to measure a reference resonance frequency without reaction with the target material; and 
 a sensing unit configured to sense the target material, based on the modified resonance frequency and the reference resonance frequency. 
 
     
     
       19. A bulk acoustic wave resonator (BAWR) sensor, comprising:
 a signal BAWR comprising:
 a first substrate; 
 a first bulk acoustic wave resonance unit comprising a first air cavity formed on a top of the first substrate, a first lower portion electrode formed on top of the first air cavity, a first piezoelectric layer formed on top of the first lower portion electrode, a first upper portion electrode formed one top of the first piezoelectric layer, and a coated layer; and 
 a first resonance frequency measuring unit configured to measure a resonance frequency modified due to a reaction with a target material using the first lower portion electrode and the first upper portion electrode, wherein the first resonance frequency measuring unit is connected to an area of the first lower portion electrode that is exposed above the first substrate, and is connected to an area of the first upper portion electrode that is exposed above the first substrate; 
 
 a reference BAWR configured to measure a reference resonance frequency without reaction with an external environment; and 
 a sensing unit configured to sense the target material, based on the modified resonance frequency and the reference resonance frequency. 
 
     
     
       20. The BAWR sensor of  claim 19 , wherein the signal BAWR comprises an in-channel and an out-channel configured to allow a sample including the target material to flow in and out from an external side to the first air cavity through a via-hole formed on the first substrate corresponding to a lower portion of the first air cavity. 
     
     
       21. The BAWR sensor of  claim 19 , wherein the reference BAWR comprises:
 a third substrate; 
 a second BAWR unit comprising a second air cavity formed on a top of the third substrate, a second lower portion electrode formed on top of the second air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, and a second upper portion electrode formed on top of the second piezoelectric layer; 
 a fourth substrate comprising a third air cavity formed on a predetermined area of the fourth substrate, and connected to the third substrate; and 
 a second resonance frequency measuring unit configured to measure the reference resonance frequency, through the second lower portion electrode and the second upper portion electrode. 
 
     
     
       22. The BAWR sensor of  claim 21 , wherein the first substrate comprises a hole, corresponding to the first air cavity, formed based on an etching scheme so that an overall area of the signal BAWR is exposed to the external environment. 
     
     
       23. The BAWR sensor of  claim 19 , wherein:
 the signal BAWR comprises:
 a second substrate comprising a second air cavity formed on a predetermined area of a lower side of the second substrate, and connected to the first substrate; 
 a first in-channel through which a sample including the target material flows in; and 
 a first out-channel through which the sample including the target material flows out; and 
 
 the reference BAWR comprises:
 a third substrate; 
 a second bulk acoustic wave resonance unit comprising a third air cavity formed on a top of the third substrate, a second lower portion electrode formed on a top of the third air cavity, a second piezoelectric layer formed on top of the second lower portion electrode, and a second upper portion electrode formed on top of the second piezoelectric layer; 
 a fourth substrate comprising a fourth air cavity formed on a predetermined area of a lower side of the fourth substrate, and connected to the third substrate; and 
 a second resonance frequency measuring unit configured to measure the reference resonance frequency using the second lower portion electrode and the second upper portion electrode, wherein the second resonance frequency measuring unit is connected to an area of the second lower portion electrode that is exposed above the third substrate, and is connected to an area of the second upper portion electrode that is exposed above the third substrate. 
 
 
     
     
       24. The BAWR sensor of  claim 23 , wherein:
 the first lower portion electrode and the first upper portion electrode are formed by a conductive material patterned on the top of the first substrate and an external side of the second substrate; and 
 the second lower portion electrode and the second upper portion electrode are formed by a conductive material patterned on the top of the third substrate and an external side of the fourth substrate.